Metal drill bits are useful in many different situations, but the most common uses are in the construction and machining industries. High-speed steel and carbide drill bits are the most common and can cut into different types of metals as well as softer material such as wood and plastic. Specialised metal drill bits can cut material such as glass, ceramics or porcelain.
Milling Machines - Metal drill bits are used in milling machines of all types. In manual milling machines such as Bridgeport's, they're used to cut holes in various materials such as metal, plastic graphite and wood. There are different types of bits for the materials that must be drilled, including high-speed steel, cobalt and carbide--the latter being the hardest of the three and used primarily for hardened steel and iron. Drill bits come in many sizes, from as small as 1/20 inch in diameter to more than 1 inch.
Construction - Construction workers rely on metal bits for drilling holes in the many different materials. Drill bits are used to make different hole sizes in materials such as wood, plastic, metal and concrete. The type of drill varies based on the material as well. Twist drills are the most common type and are good for straight holes less than 1 inch in diameter. Metal bits can drill pilot holes, and are also used to make larger holes to run wiring through framing.
Lathe Work - Lathes are used to cut material while it's spinning, and metal bits are essential when drilling holes in material on center. Whether a metal or wood-working lathe is used, a drill bit can be useful to open up the center of material that's being spun. With metal lathes, the drill bit is held in the tailstock on manual machines and in the tool turret of CNC lathes. The turning speed is adjusted based on the material being cut, and the material from which the drill bit is made, to avoid damage to the tool or the raw material.
Tile and Glass Work - Diamonds are among the hardest materials on Earth. Diamond-tipped metal drill bits are perfectly suited for cutting glass, ceramic and porcelain. When diamonds are mined, the small chips or diamonds not suitable for sale in jewelry are often sold for industrial use. Diamond-tipped drills have shafts made of steel with diamonds on the ends to prevent cracking and chipping when cutting glass, ceramics or porcelain. The diamond tip provides the metal drill with grip when used on slippery surfaces, so regular metal drills are not used to cut these types of materials.